1<?php
2/**
3 * Redis-backed job queue code.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 * http://www.gnu.org/copyleft/gpl.html
19 *
20 * @file
21 */
22
23use MediaWiki\Logger\LoggerFactory;
24use Psr\Log\LoggerInterface;
25
26/**
27 * Class to handle job queues stored in Redis
28 *
29 * This is a faster and less resource-intensive job queue than JobQueueDB.
30 * All data for a queue using this class is placed into one redis server.
31 * The mediawiki/services/jobrunner background service must be set up and running.
32 *
33 * There are eight main redis keys (per queue) used to track jobs:
34 *   - l-unclaimed  : A list of job IDs used for ready unclaimed jobs
35 *   - z-claimed    : A sorted set of (job ID, UNIX timestamp as score) used for job retries
36 *   - z-abandoned  : A sorted set of (job ID, UNIX timestamp as score) used for broken jobs
37 *   - z-delayed    : A sorted set of (job ID, UNIX timestamp as score) used for delayed jobs
38 *   - h-idBySha1   : A hash of (SHA1 => job ID) for unclaimed jobs used for de-duplication
39 *   - h-sha1ById   : A hash of (job ID => SHA1) for unclaimed jobs used for de-duplication
40 *   - h-attempts   : A hash of (job ID => attempt count) used for job claiming/retries
41 *   - h-data       : A hash of (job ID => serialized blobs) for job storage
42 * A job ID can be in only one of z-delayed, l-unclaimed, z-claimed, and z-abandoned.
43 * If an ID appears in any of those lists, it should have a h-data entry for its ID.
44 * If a job has a SHA1 de-duplication value and its ID is in l-unclaimed or z-delayed, then
45 * there should be no other such jobs with that SHA1. Every h-idBySha1 entry has an h-sha1ById
46 * entry and every h-sha1ById must refer to an ID that is l-unclaimed. If a job has its
47 * ID in z-claimed or z-abandoned, then it must also have an h-attempts entry for its ID.
48 *
49 * The following keys are used to track queue states:
50 *   - s-queuesWithJobs : A set of all queues with non-abandoned jobs
51 *
52 * The background service takes care of undelaying, recycling, and pruning jobs as well as
53 * removing s-queuesWithJobs entries as queues empty.
54 *
55 * Additionally, "rootjob:* keys track "root jobs" used for additional de-duplication.
56 * Aside from root job keys, all keys have no expiry, and are only removed when jobs are run.
57 * All the keys are prefixed with the relevant wiki ID information.
58 *
59 * This class requires Redis 2.6 as it makes use Lua scripts for fast atomic operations.
60 * Additionally, it should be noted that redis has different persistence modes, such
61 * as rdb snapshots, journaling, and no persistence. Appropriate configuration should be
62 * made on the servers based on what queues are using it and what tolerance they have.
63 *
64 * @ingroup JobQueue
65 * @ingroup Redis
66 * @since 1.22
67 */
68class JobQueueRedis extends JobQueue {
69	/** @var RedisConnectionPool */
70	protected $redisPool;
71	/** @var LoggerInterface */
72	protected $logger;
73
74	/** @var string Server address */
75	protected $server;
76	/** @var string Compression method to use */
77	protected $compression;
78
79	private const MAX_PUSH_SIZE = 25; // avoid tying up the server
80
81	/**
82	 * @param array $params Possible keys:
83	 *   - redisConfig : An array of parameters to RedisConnectionPool::__construct().
84	 *                   Note that the serializer option is ignored as "none" is always used.
85	 *   - redisServer : A hostname/port combination or the absolute path of a UNIX socket.
86	 *                   If a hostname is specified but no port, the standard port number
87	 *                   6379 will be used. Required.
88	 *   - compression : The type of compression to use; one of (none,gzip).
89	 *   - daemonized  : Set to true if the redisJobRunnerService runs in the background.
90	 *                   This will disable job recycling/undelaying from the MediaWiki side
91	 *                   to avoid redundance and out-of-sync configuration.
92	 * @throws InvalidArgumentException
93	 */
94	public function __construct( array $params ) {
95		parent::__construct( $params );
96		$params['redisConfig']['serializer'] = 'none'; // make it easy to use Lua
97		$this->server = $params['redisServer'];
98		$this->compression = $params['compression'] ?? 'none';
99		$this->redisPool = RedisConnectionPool::singleton( $params['redisConfig'] );
100		if ( empty( $params['daemonized'] ) ) {
101			throw new InvalidArgumentException(
102				"Non-daemonized mode is no longer supported. Please install the " .
103				"mediawiki/services/jobrunner service and update \$wgJobTypeConf as needed." );
104		}
105		$this->logger = LoggerFactory::getInstance( 'redis' );
106	}
107
108	protected function supportedOrders() {
109		return [ 'timestamp', 'fifo' ];
110	}
111
112	protected function optimalOrder() {
113		return 'fifo';
114	}
115
116	protected function supportsDelayedJobs() {
117		return true;
118	}
119
120	/**
121	 * @see JobQueue::doIsEmpty()
122	 * @return bool
123	 * @throws JobQueueError
124	 */
125	protected function doIsEmpty() {
126		return $this->doGetSize() == 0;
127	}
128
129	/**
130	 * @see JobQueue::doGetSize()
131	 * @return int
132	 * @throws JobQueueError
133	 */
134	protected function doGetSize() {
135		$conn = $this->getConnection();
136		try {
137			return $conn->lLen( $this->getQueueKey( 'l-unclaimed' ) );
138		} catch ( RedisException $e ) {
139			throw $this->handleErrorAndMakeException( $conn, $e );
140		}
141	}
142
143	/**
144	 * @see JobQueue::doGetAcquiredCount()
145	 * @return int
146	 * @throws JobQueueError
147	 */
148	protected function doGetAcquiredCount() {
149		$conn = $this->getConnection();
150		try {
151			$conn->multi( Redis::PIPELINE );
152			$conn->zCard( $this->getQueueKey( 'z-claimed' ) );
153			$conn->zCard( $this->getQueueKey( 'z-abandoned' ) );
154
155			return array_sum( $conn->exec() );
156		} catch ( RedisException $e ) {
157			throw $this->handleErrorAndMakeException( $conn, $e );
158		}
159	}
160
161	/**
162	 * @see JobQueue::doGetDelayedCount()
163	 * @return int
164	 * @throws JobQueueError
165	 */
166	protected function doGetDelayedCount() {
167		$conn = $this->getConnection();
168		try {
169			return $conn->zCard( $this->getQueueKey( 'z-delayed' ) );
170		} catch ( RedisException $e ) {
171			throw $this->handleErrorAndMakeException( $conn, $e );
172		}
173	}
174
175	/**
176	 * @see JobQueue::doGetAbandonedCount()
177	 * @return int
178	 * @throws JobQueueError
179	 */
180	protected function doGetAbandonedCount() {
181		$conn = $this->getConnection();
182		try {
183			return $conn->zCard( $this->getQueueKey( 'z-abandoned' ) );
184		} catch ( RedisException $e ) {
185			throw $this->handleErrorAndMakeException( $conn, $e );
186		}
187	}
188
189	/**
190	 * @see JobQueue::doBatchPush()
191	 * @param IJobSpecification[] $jobs
192	 * @param int $flags
193	 * @return void
194	 * @throws JobQueueError
195	 */
196	protected function doBatchPush( array $jobs, $flags ) {
197		// Convert the jobs into field maps (de-duplicated against each other)
198		$items = []; // (job ID => job fields map)
199		foreach ( $jobs as $job ) {
200			$item = $this->getNewJobFields( $job );
201			if ( strlen( $item['sha1'] ) ) { // hash identifier => de-duplicate
202				$items[$item['sha1']] = $item;
203			} else {
204				$items[$item['uuid']] = $item;
205			}
206		}
207
208		if ( $items === [] ) {
209			return; // nothing to do
210		}
211
212		$conn = $this->getConnection();
213		try {
214			// Actually push the non-duplicate jobs into the queue...
215			if ( $flags & self::QOS_ATOMIC ) {
216				$batches = [ $items ]; // all or nothing
217			} else {
218				$batches = array_chunk( $items, self::MAX_PUSH_SIZE );
219			}
220			$failed = 0;
221			$pushed = 0;
222			foreach ( $batches as $itemBatch ) {
223				$added = $this->pushBlobs( $conn, $itemBatch );
224				if ( is_int( $added ) ) {
225					$pushed += $added;
226				} else {
227					$failed += count( $itemBatch );
228				}
229			}
230			$this->incrStats( 'inserts', $this->type, count( $items ) );
231			$this->incrStats( 'inserts_actual', $this->type, $pushed );
232			$this->incrStats( 'dupe_inserts', $this->type,
233				count( $items ) - $failed - $pushed );
234			if ( $failed > 0 ) {
235				$err = "Could not insert {$failed} {$this->type} job(s).";
236				wfDebugLog( 'JobQueueRedis', $err );
237				throw new RedisException( $err );
238			}
239		} catch ( RedisException $e ) {
240			throw $this->handleErrorAndMakeException( $conn, $e );
241		}
242	}
243
244	/**
245	 * @param RedisConnRef $conn
246	 * @param array[] $items List of results from JobQueueRedis::getNewJobFields()
247	 * @return int Number of jobs inserted (duplicates are ignored)
248	 * @throws RedisException
249	 */
250	protected function pushBlobs( RedisConnRef $conn, array $items ) {
251		$args = [ $this->encodeQueueName() ];
252		// Next args come in 4s ([id, sha1, rtime, blob [, id, sha1, rtime, blob ... ] ] )
253		foreach ( $items as $item ) {
254			$args[] = (string)$item['uuid'];
255			$args[] = (string)$item['sha1'];
256			$args[] = (string)$item['rtimestamp'];
257			$args[] = (string)$this->serialize( $item );
258		}
259		static $script =
260		/** @lang Lua */
261<<<LUA
262		local kUnclaimed, kSha1ById, kIdBySha1, kDelayed, kData, kQwJobs = unpack(KEYS)
263		-- First argument is the queue ID
264		local queueId = ARGV[1]
265		-- Next arguments all come in 4s (one per job)
266		local variadicArgCount = #ARGV - 1
267		if variadicArgCount % 4 ~= 0 then
268			return redis.error_reply('Unmatched arguments')
269		end
270		-- Insert each job into this queue as needed
271		local pushed = 0
272		for i = 2,#ARGV,4 do
273			local id,sha1,rtimestamp,blob = ARGV[i],ARGV[i+1],ARGV[i+2],ARGV[i+3]
274			if sha1 == '' or redis.call('hExists',kIdBySha1,sha1) == 0 then
275				if 1*rtimestamp > 0 then
276					-- Insert into delayed queue (release time as score)
277					redis.call('zAdd',kDelayed,rtimestamp,id)
278				else
279					-- Insert into unclaimed queue
280					redis.call('lPush',kUnclaimed,id)
281				end
282				if sha1 ~= '' then
283					redis.call('hSet',kSha1ById,id,sha1)
284					redis.call('hSet',kIdBySha1,sha1,id)
285				end
286				redis.call('hSet',kData,id,blob)
287				pushed = pushed + 1
288			end
289		end
290		-- Mark this queue as having jobs
291		redis.call('sAdd',kQwJobs,queueId)
292		return pushed
293LUA;
294		return $conn->luaEval( $script,
295			array_merge(
296				[
297					$this->getQueueKey( 'l-unclaimed' ), # KEYS[1]
298					$this->getQueueKey( 'h-sha1ById' ), # KEYS[2]
299					$this->getQueueKey( 'h-idBySha1' ), # KEYS[3]
300					$this->getQueueKey( 'z-delayed' ), # KEYS[4]
301					$this->getQueueKey( 'h-data' ), # KEYS[5]
302					$this->getGlobalKey( 's-queuesWithJobs' ), # KEYS[6]
303				],
304				$args
305			),
306			6 # number of first argument(s) that are keys
307		);
308	}
309
310	/**
311	 * @see JobQueue::doPop()
312	 * @return RunnableJob|bool
313	 * @throws JobQueueError
314	 */
315	protected function doPop() {
316		$job = false;
317
318		$conn = $this->getConnection();
319		try {
320			do {
321				$blob = $this->popAndAcquireBlob( $conn );
322				if ( !is_string( $blob ) ) {
323					break; // no jobs; nothing to do
324				}
325
326				$this->incrStats( 'pops', $this->type );
327				$item = $this->unserialize( $blob );
328				if ( $item === false ) {
329					wfDebugLog( 'JobQueueRedis', "Could not unserialize {$this->type} job." );
330					continue;
331				}
332
333				// If $item is invalid, the runner loop recyling will cleanup as needed
334				$job = $this->getJobFromFields( $item ); // may be false
335			} while ( !$job ); // job may be false if invalid
336		} catch ( RedisException $e ) {
337			throw $this->handleErrorAndMakeException( $conn, $e );
338		}
339
340		return $job;
341	}
342
343	/**
344	 * @param RedisConnRef $conn
345	 * @return array Serialized string or false
346	 * @throws RedisException
347	 */
348	protected function popAndAcquireBlob( RedisConnRef $conn ) {
349		static $script =
350		/** @lang Lua */
351<<<LUA
352		local kUnclaimed, kSha1ById, kIdBySha1, kClaimed, kAttempts, kData = unpack(KEYS)
353		local rTime = unpack(ARGV)
354		-- Pop an item off the queue
355		local id = redis.call('rPop',kUnclaimed)
356		if not id then
357			return false
358		end
359		-- Allow new duplicates of this job
360		local sha1 = redis.call('hGet',kSha1ById,id)
361		if sha1 then redis.call('hDel',kIdBySha1,sha1) end
362		redis.call('hDel',kSha1ById,id)
363		-- Mark the jobs as claimed and return it
364		redis.call('zAdd',kClaimed,rTime,id)
365		redis.call('hIncrBy',kAttempts,id,1)
366		return redis.call('hGet',kData,id)
367LUA;
368		return $conn->luaEval( $script,
369			[
370				$this->getQueueKey( 'l-unclaimed' ), # KEYS[1]
371				$this->getQueueKey( 'h-sha1ById' ), # KEYS[2]
372				$this->getQueueKey( 'h-idBySha1' ), # KEYS[3]
373				$this->getQueueKey( 'z-claimed' ), # KEYS[4]
374				$this->getQueueKey( 'h-attempts' ), # KEYS[5]
375				$this->getQueueKey( 'h-data' ), # KEYS[6]
376				time(), # ARGV[1] (injected to be replication-safe)
377			],
378			6 # number of first argument(s) that are keys
379		);
380	}
381
382	/**
383	 * @see JobQueue::doAck()
384	 * @param RunnableJob $job
385	 * @return RunnableJob|bool
386	 * @throws UnexpectedValueException
387	 * @throws JobQueueError
388	 */
389	protected function doAck( RunnableJob $job ) {
390		$uuid = $job->getMetadata( 'uuid' );
391		if ( $uuid === null ) {
392			throw new UnexpectedValueException( "Job of type '{$job->getType()}' has no UUID." );
393		}
394
395		$conn = $this->getConnection();
396		try {
397			static $script =
398			/** @lang Lua */
399<<<LUA
400			local kClaimed, kAttempts, kData = unpack(KEYS)
401			local id = unpack(ARGV)
402			-- Unmark the job as claimed
403			local removed = redis.call('zRem',kClaimed,id)
404			-- Check if the job was recycled
405			if removed == 0 then
406				return 0
407			end
408			-- Delete the retry data
409			redis.call('hDel',kAttempts,id)
410			-- Delete the job data itself
411			return redis.call('hDel',kData,id)
412LUA;
413			$res = $conn->luaEval( $script,
414				[
415					$this->getQueueKey( 'z-claimed' ), # KEYS[1]
416					$this->getQueueKey( 'h-attempts' ), # KEYS[2]
417					$this->getQueueKey( 'h-data' ), # KEYS[3]
418					$uuid # ARGV[1]
419				],
420				3 # number of first argument(s) that are keys
421			);
422
423			if ( !$res ) {
424				wfDebugLog( 'JobQueueRedis', "Could not acknowledge {$this->type} job $uuid." );
425
426				return false;
427			}
428
429			$this->incrStats( 'acks', $this->type );
430		} catch ( RedisException $e ) {
431			throw $this->handleErrorAndMakeException( $conn, $e );
432		}
433
434		return true;
435	}
436
437	/**
438	 * @see JobQueue::doDeduplicateRootJob()
439	 * @param IJobSpecification $job
440	 * @return bool
441	 * @throws JobQueueError
442	 * @throws LogicException
443	 */
444	protected function doDeduplicateRootJob( IJobSpecification $job ) {
445		if ( !$job->hasRootJobParams() ) {
446			throw new LogicException( "Cannot register root job; missing parameters." );
447		}
448		$params = $job->getRootJobParams();
449
450		$key = $this->getRootJobCacheKey( $params['rootJobSignature'] );
451
452		$conn = $this->getConnection();
453		try {
454			$timestamp = $conn->get( $key ); // last known timestamp of such a root job
455			if ( $timestamp && $timestamp >= $params['rootJobTimestamp'] ) {
456				return true; // a newer version of this root job was enqueued
457			}
458
459			// Update the timestamp of the last root job started at the location...
460			return $conn->set( $key, $params['rootJobTimestamp'], self::ROOTJOB_TTL ); // 2 weeks
461		} catch ( RedisException $e ) {
462			throw $this->handleErrorAndMakeException( $conn, $e );
463		}
464	}
465
466	/**
467	 * @see JobQueue::doIsRootJobOldDuplicate()
468	 * @param IJobSpecification $job
469	 * @return bool
470	 * @throws JobQueueError
471	 */
472	protected function doIsRootJobOldDuplicate( IJobSpecification $job ) {
473		if ( !$job->hasRootJobParams() ) {
474			return false; // job has no de-deplication info
475		}
476		$params = $job->getRootJobParams();
477
478		$conn = $this->getConnection();
479		try {
480			// Get the last time this root job was enqueued
481			$timestamp = $conn->get( $this->getRootJobCacheKey( $params['rootJobSignature'] ) );
482		} catch ( RedisException $e ) {
483			throw $this->handleErrorAndMakeException( $conn, $e );
484		}
485
486		// Check if a new root job was started at the location after this one's...
487		return ( $timestamp && $timestamp > $params['rootJobTimestamp'] );
488	}
489
490	/**
491	 * @see JobQueue::doDelete()
492	 * @return bool
493	 * @throws JobQueueError
494	 */
495	protected function doDelete() {
496		static $props = [ 'l-unclaimed', 'z-claimed', 'z-abandoned',
497			'z-delayed', 'h-idBySha1', 'h-sha1ById', 'h-attempts', 'h-data' ];
498
499		$conn = $this->getConnection();
500		try {
501			$keys = [];
502			foreach ( $props as $prop ) {
503				$keys[] = $this->getQueueKey( $prop );
504			}
505
506			$ok = ( $conn->del( $keys ) !== false );
507			$conn->sRem( $this->getGlobalKey( 's-queuesWithJobs' ), $this->encodeQueueName() );
508
509			return $ok;
510		} catch ( RedisException $e ) {
511			throw $this->handleErrorAndMakeException( $conn, $e );
512		}
513	}
514
515	/**
516	 * @see JobQueue::getAllQueuedJobs()
517	 * @return Iterator
518	 * @throws JobQueueError
519	 */
520	public function getAllQueuedJobs() {
521		$conn = $this->getConnection();
522		try {
523			$uids = $conn->lRange( $this->getQueueKey( 'l-unclaimed' ), 0, -1 );
524		} catch ( RedisException $e ) {
525			throw $this->handleErrorAndMakeException( $conn, $e );
526		}
527
528		return $this->getJobIterator( $conn, $uids );
529	}
530
531	/**
532	 * @see JobQueue::getAllDelayedJobs()
533	 * @return Iterator
534	 * @throws JobQueueError
535	 */
536	public function getAllDelayedJobs() {
537		$conn = $this->getConnection();
538		try {
539			$uids = $conn->zRange( $this->getQueueKey( 'z-delayed' ), 0, -1 );
540		} catch ( RedisException $e ) {
541			throw $this->handleErrorAndMakeException( $conn, $e );
542		}
543
544		return $this->getJobIterator( $conn, $uids );
545	}
546
547	/**
548	 * @see JobQueue::getAllAcquiredJobs()
549	 * @return Iterator
550	 * @throws JobQueueError
551	 */
552	public function getAllAcquiredJobs() {
553		$conn = $this->getConnection();
554		try {
555			$uids = $conn->zRange( $this->getQueueKey( 'z-claimed' ), 0, -1 );
556		} catch ( RedisException $e ) {
557			throw $this->handleErrorAndMakeException( $conn, $e );
558		}
559
560		return $this->getJobIterator( $conn, $uids );
561	}
562
563	/**
564	 * @see JobQueue::getAllAbandonedJobs()
565	 * @return Iterator
566	 * @throws JobQueueError
567	 */
568	public function getAllAbandonedJobs() {
569		$conn = $this->getConnection();
570		try {
571			$uids = $conn->zRange( $this->getQueueKey( 'z-abandoned' ), 0, -1 );
572		} catch ( RedisException $e ) {
573			throw $this->handleErrorAndMakeException( $conn, $e );
574		}
575
576		return $this->getJobIterator( $conn, $uids );
577	}
578
579	/**
580	 * @param RedisConnRef $conn
581	 * @param array $uids List of job UUIDs
582	 * @return MappedIterator
583	 */
584	protected function getJobIterator( RedisConnRef $conn, array $uids ) {
585		return new MappedIterator(
586			$uids,
587			function ( $uid ) use ( $conn ) {
588				return $this->getJobFromUidInternal( $uid, $conn );
589			},
590			[ 'accept' => static function ( $job ) {
591				return is_object( $job );
592			} ]
593		);
594	}
595
596	public function getCoalesceLocationInternal() {
597		return "RedisServer:" . $this->server;
598	}
599
600	protected function doGetSiblingQueuesWithJobs( array $types ) {
601		return array_keys( array_filter( $this->doGetSiblingQueueSizes( $types ) ) );
602	}
603
604	protected function doGetSiblingQueueSizes( array $types ) {
605		$sizes = []; // (type => size)
606		$types = array_values( $types ); // reindex
607		$conn = $this->getConnection();
608		try {
609			$conn->multi( Redis::PIPELINE );
610			foreach ( $types as $type ) {
611				$conn->lLen( $this->getQueueKey( 'l-unclaimed', $type ) );
612			}
613			$res = $conn->exec();
614			if ( is_array( $res ) ) {
615				foreach ( $res as $i => $size ) {
616					$sizes[$types[$i]] = $size;
617				}
618			}
619		} catch ( RedisException $e ) {
620			throw $this->handleErrorAndMakeException( $conn, $e );
621		}
622
623		return $sizes;
624	}
625
626	/**
627	 * This function should not be called outside JobQueueRedis
628	 *
629	 * @param string $uid
630	 * @param RedisConnRef|Redis $conn
631	 * @return RunnableJob|bool Returns false if the job does not exist
632	 * @throws JobQueueError
633	 * @throws UnexpectedValueException
634	 */
635	public function getJobFromUidInternal( $uid, $conn ) {
636		try {
637			$data = $conn->hGet( $this->getQueueKey( 'h-data' ), $uid );
638			if ( $data === false ) {
639				return false; // not found
640			}
641			$item = $this->unserialize( $data );
642			if ( !is_array( $item ) ) { // this shouldn't happen
643				throw new UnexpectedValueException( "Could not unserialize job with ID '$uid'." );
644			}
645
646			$params = $item['params'];
647			$params += [ 'namespace' => $item['namespace'], 'title' => $item['title'] ];
648			$job = $this->factoryJob( $item['type'], $params );
649			$job->setMetadata( 'uuid', $item['uuid'] );
650			$job->setMetadata( 'timestamp', $item['timestamp'] );
651			// Add in attempt count for debugging at showJobs.php
652			$job->setMetadata( 'attempts',
653				$conn->hGet( $this->getQueueKey( 'h-attempts' ), $uid ) );
654
655			return $job;
656		} catch ( RedisException $e ) {
657			throw $this->handleErrorAndMakeException( $conn, $e );
658		}
659	}
660
661	/**
662	 * @return array List of (wiki,type) tuples for queues with non-abandoned jobs
663	 * @throws JobQueueConnectionError
664	 * @throws JobQueueError
665	 */
666	public function getServerQueuesWithJobs() {
667		$queues = [];
668
669		$conn = $this->getConnection();
670		try {
671			$set = $conn->sMembers( $this->getGlobalKey( 's-queuesWithJobs' ) );
672			foreach ( $set as $queue ) {
673				$queues[] = $this->decodeQueueName( $queue );
674			}
675		} catch ( RedisException $e ) {
676			throw $this->handleErrorAndMakeException( $conn, $e );
677		}
678
679		return $queues;
680	}
681
682	/**
683	 * @param IJobSpecification $job
684	 * @return array
685	 */
686	protected function getNewJobFields( IJobSpecification $job ) {
687		return [
688			// Fields that describe the nature of the job
689			'type' => $job->getType(),
690			'namespace' => $job->getParams()['namespace'] ?? NS_SPECIAL,
691			'title' => $job->getParams()['title'] ?? '',
692			'params' => $job->getParams(),
693			// Some jobs cannot run until a "release timestamp"
694			'rtimestamp' => $job->getReleaseTimestamp() ?: 0,
695			// Additional job metadata
696			'uuid' => $this->idGenerator->newRawUUIDv4(),
697			'sha1' => $job->ignoreDuplicates()
698				? Wikimedia\base_convert( sha1( serialize( $job->getDeduplicationInfo() ) ), 16, 36, 31 )
699				: '',
700			'timestamp' => time() // UNIX timestamp
701		];
702	}
703
704	/**
705	 * @param array $fields
706	 * @return RunnableJob|bool
707	 */
708	protected function getJobFromFields( array $fields ) {
709		$params = $fields['params'];
710		$params += [ 'namespace' => $fields['namespace'], 'title' => $fields['title'] ];
711
712		$job = $this->factoryJob( $fields['type'], $params );
713		$job->setMetadata( 'uuid', $fields['uuid'] );
714		$job->setMetadata( 'timestamp', $fields['timestamp'] );
715
716		return $job;
717	}
718
719	/**
720	 * @param array $fields
721	 * @return string Serialized and possibly compressed version of $fields
722	 */
723	protected function serialize( array $fields ) {
724		$blob = serialize( $fields );
725		if ( $this->compression === 'gzip'
726			&& strlen( $blob ) >= 1024
727			&& function_exists( 'gzdeflate' )
728		) {
729			$object = (object)[ 'blob' => gzdeflate( $blob ), 'enc' => 'gzip' ];
730			$blobz = serialize( $object );
731
732			return ( strlen( $blobz ) < strlen( $blob ) ) ? $blobz : $blob;
733		} else {
734			return $blob;
735		}
736	}
737
738	/**
739	 * @param string $blob
740	 * @return array|bool Unserialized version of $blob or false
741	 */
742	protected function unserialize( $blob ) {
743		$fields = unserialize( $blob );
744		if ( is_object( $fields ) ) {
745			if ( $fields->enc === 'gzip' && function_exists( 'gzinflate' ) ) {
746				$fields = unserialize( gzinflate( $fields->blob ) );
747			} else {
748				$fields = false;
749			}
750		}
751
752		return is_array( $fields ) ? $fields : false;
753	}
754
755	/**
756	 * Get a connection to the server that handles all sub-queues for this queue
757	 *
758	 * @return RedisConnRef|Redis
759	 * @throws JobQueueConnectionError
760	 */
761	protected function getConnection() {
762		$conn = $this->redisPool->getConnection( $this->server, $this->logger );
763		if ( !$conn ) {
764			throw new JobQueueConnectionError(
765				"Unable to connect to redis server {$this->server}." );
766		}
767
768		return $conn;
769	}
770
771	/**
772	 * @param RedisConnRef $conn
773	 * @param RedisException $e
774	 * @return JobQueueError
775	 */
776	protected function handleErrorAndMakeException( RedisConnRef $conn, $e ) {
777		$this->redisPool->handleError( $conn, $e );
778		return new JobQueueError( "Redis server error: {$e->getMessage()}\n" );
779	}
780
781	/**
782	 * @return string JSON
783	 */
784	private function encodeQueueName() {
785		return json_encode( [ $this->type, $this->domain ] );
786	}
787
788	/**
789	 * @param string $name JSON
790	 * @return array (type, wiki)
791	 */
792	private function decodeQueueName( $name ) {
793		return json_decode( $name );
794	}
795
796	/**
797	 * @param string $name
798	 * @return string
799	 */
800	private function getGlobalKey( $name ) {
801		$parts = [ 'global', 'jobqueue', $name ];
802		foreach ( $parts as $part ) {
803			if ( !preg_match( '/[a-zA-Z0-9_-]+/', $part ) ) {
804				throw new InvalidArgumentException( "Key part characters are out of range." );
805			}
806		}
807
808		return implode( ':', $parts );
809	}
810
811	/**
812	 * @param string $prop
813	 * @param string|null $type Override this for sibling queues
814	 * @return string
815	 */
816	private function getQueueKey( $prop, $type = null ) {
817		$type = is_string( $type ) ? $type : $this->type;
818
819		// Use wiki ID for b/c
820		$keyspace = WikiMap::getWikiIdFromDbDomain( $this->domain );
821
822		$parts = [ $keyspace, 'jobqueue', $type, $prop ];
823
824		// Parts are typically ASCII, but encode for sanity to escape ":"
825		return implode( ':', array_map( 'rawurlencode', $parts ) );
826	}
827}
828